I-Tech IT8500plus Series Operating instructions

DC Programmable Electronic
Load
Series IT8500+ Programming Guide
Model: IT8511+/IT8511A+/IT8512+/IT8512A+/
IT8512B+/IT8512C+/IT8512H+/IT8513A+/
IT8513B+/IT8513C+/IT8514C+/IT8514B+/
IT8516C+
Revision: V1.2

Statement
© Itech Electronic, Co., Ltd. 2018 No
part of this manual may be reproduced
in any form or by any means (including
electronic storage and retrieval or
translation into a foreign language)
without prior permission and written
consent from Itech Electronic, Co., Ltd.
as governed by international copyright
laws.
Manual Article No.
IT8500+-402158
Revision
Revision 1, published on
May 4th, 2018
Itech Electronic, Co., Ltd.
Trademark Statement
Pentium is a registered trademark of
Intel Corporation in the United States.
Microsoft, Visual Studio, Windows and
MS Windows are trademarks of
Microsoft Corporation in the United
States and/or other countries/regions.
Guarantee
Materials in the document are provided
talis qualis and may be changed in
future revisions without prior notice. In
addition, within the maximum allowable
extent of laws, ITECH is not committed
to any explicit or implied guarantee for
this manual and all information therein,
including but not limited to the implied
guarantee on marketability and
availability for some special purposes.
ITECH shall not be responsible for any
error or incidental or indirect losses
caused by the provision, use or
application of this documents and
information therein. If some guarantee
clauses in other written agreements
between ITECH and users are not
consistent with clauses herein, those
clauses in other written agreements
shall prevail.
Technology license
Hardware and/or software in this
document cannot be provided without a
license and can only be used or copied
according to the license.
Restricted permission statement
Restricted permissions of the U.S.
government. Permissions for software
and technical data which are authorized
to the U.S. Government only include
those for custom provision to end users.
ITECH follows FAR 12.211 (technical
data), 12.212 (computer software).
DFARS 252.227-7015 (technical
data--commercial products) for national
defense and DFARS 227.7202-3
(permissions for commercial computer
software or computer software
documents) while providing the
customized business licenses of
software and technical data.
Safety Statement
“Caution” signs indicate danger. It is
required to pay attention to the contents
of these signs during implementation of
operations.
The damage to the product or loss of
important data may be caused in case of
improper operation steps or failure to
follow operation steps. Do not continue
to implement any improper operation
indicated in “Caution” signs when the
specified conditions are not fully
understood or these conditions are not
satisfied.
“Warning” indicates danger. It is
required to pay attention to the contents
of these signs during implementation of
operation steps. Personal casualties
may be caused in case of improper
operation steps or failure to follow these
operation steps. Do not continue to
implement any improper operation
indicated in “Warning” signs when the
specified conditions are not fully
understood or these conditions are not
satisfied.
NOTE
“Instructions” indicates operation
instructions. It is required to refer to the
contents of these signs during operation
steps. These signs are used for
providing tips or supplementary
information for operators.

IT8500+ Programming Guide
Copyright © ITECH Electronic Co., Ltd. i
Certification and Quality Assurance
IT8500+ series electronic load completely reaches nominal technical indicators
in the manual.
Warranty Service
ITECH Company will provide one-year warranty services for the product
materials and manufacturing (excluding the following limitations).
⚫When warranty service or repair is needed, please send the product to the
service unit specified by ITECH Company.
⚫When the product is sent to ITECH Company for warranty service, the
customer must pay the one-way freight to the maintenance department of
ITECH, and ITECH will be responsible for return freight.
⚫If the product is sent to ITECH for warranty service from other countries,
the customer will be responsible for all the freight, duties and other taxes.
Limitation of Warranty
Warranty service does not apply to the damage caused in the following
circumstances:
⚫Damage resulting from customer-wired circuits or customer-supplied parts
or accessories;
⚫Product which has been modified or repaired by the customer;
⚫Damage caused by the circuit installed by the customer or damage caused
by operation of the product in non-specified environment;
⚫The product model or serial number is altered, deleted, removed or made
illegible by customer;
⚫Damage caused by accidents, including but not limited to lightning, water,
fire, abuse or negligence.
Safety Signs
DC power
ON (with the power
switched on)
AC power
OFF (with the power
supply switched off)
Both DC and AC power supply
Power supply
switching-on status
Protective grounding terminal
Power supply
switching-off status
Grounding terminal
Reference terminal
Danger sign
Positive terminal
Warning sign (refer to specific
“Warning” or “Caution”
information in the manual)
Negative terminal
Ground wire connection end
sign
-
-

IT8500+ Programming Guide
Copyright © ITECH Electronic Co., Ltd. ii
Safety Precautions
General safety precautions below must be followed in each phase of instrument
operation. In case of failure to follow these precautions or specific warnings in
other parts of the manual, violation against the safety standards related to the
design, manufacture and purpose of the instrument will occur. If the user does
not follow these precautions, ITECH will bear no responsibility arising there
from.
⚫Series IT8500+ electronic load supports 110V/220VAC input and need to
switch the input voltage before operation.
⚫Do not use the instrument if it is damaged. Before operation, check the
casing to see whether it cracks. Do not operate the instrument in the
presence of inflammable gasses, vapors or dusts.
⚫The electronic load is provided with a three-core power line during delivery
and should be connected to a three-core junction box. Before operation, be
sure that the instrument is well grounded.
⚫Make sure to use the power cord supplied by ITECH.
⚫Check all marks on the instrument before connecting the instrument to
power supply.
⚫Use electric wires of appropriate load. All loading wires should be capable
of bearing maximum short-circuit current of electronic load without
overheating. If there are multiple electronic loads, each pair of the power
cord must be capable of bearing the full-loaded rated short-circuit output
current
⚫Ensure the voltage fluctuation of mains supply is less than 10% of the
working voltage range in order to reduce risks of fire and electric shock.
⚫Do not install alternative parts on the instrument or perform any
unauthorized modification.
⚫Do not use the instrument if the detachable cover is removed or loosen.
⚫To prevent the possibility of accidental injuries, be sure to use the power
adapter supplied by the manufacturer only.
⚫We do not accept responsibility for any direct or indirect financial damage
or loss of profit that might occur when using the instrument.
⚫This instrument is used for industrial purposes, do not apply this product to
IT power supply system.
⚫Never use the instrument with a life-support system or any other equipment
subject to safety requirements.
⚫Failure to use the instrument as directed by the manufacturer may render
its protective features void.
⚫Always clean the casing with a dry cloth. Do not clean the internals.
⚫Make sure the vent hole is always unblocked.
Environmental Conditions
The IT8500+ series electronic load can only be used indoors or in low
condensation areas. The following table shows general environmental

IT8500+ Programming Guide
Copyright © ITECH Electronic Co., Ltd. iii
requirements for this instrument.
Environmental conditions
Requirement
Operating temperature
0°C - 40°C
Operating humidity
20% - 80% (non condensing)
Storage temperature
-20°C - 70 °C
Altitude
≤2,000m
Pollution
Grade 2 pollution
Installation category
II
Note
In order to ensure the accuracy of measurement, it is recommended to operate the
instrument half an hour after start-up.
Regulation Tag
The CE tag shows that the product
complies with the provisions of all relevant
European laws (if the year is shown, it
indicates that the year when the design is
approved).
This instrument complies with the WEEE
directive (2002/96/EC) tag requirements.
This attached product tag shows that the
electrical/electronic product cannot be
discarded in household waste.
This symbol indicates that no danger will
happen or toxic substances will not leak or
cause damage in normal use within the
specified period. The service life of the product
is 10 years. The product can be used safely
within the environmental protection period;
otherwise, the product should be put into the
recycling system.
Waste Electrical and Electronic Equipment (WEEE)
Directive
Waste electrical and electronic equipment (WEEE)
directive, 2002/96/EC
The product complies with tag requirements of the
WEEE directive (2002/96/EC). This tag indicates that the
electronic equipment cannot be disposed of as ordinary
household waste.
Product Category
According to the equipment classification in Annex I of
the WEEE directive, this instrument belongs to the
“Monitoring” product.
If you want to return the unnecessary instrument,
please contact the nearest sales office of ITECH.

IT8500+ Programming Guide
Copyright © ITECH Electronic Co., Ltd. iv
Compliance Information
Complies with the essential requirements of the following applicable European
Directives, and carries the CE marking accordingly:
⚫Electromagnetic Compatibility (EMC) Directive 2014/30/EU
⚫Low-Voltage Directive (Safety) 2014/35/EU
Conforms with the following product standards:
EMC Standard
IEC 61326-1:2012/ EN 61326-1:2013 ¹²³
Reference Standards
CISPR 11:2009+A1:2010/ EN 55011:2009+A1:2010 (Group 1, Class A)
IEC 61000-4-2:2008/ EN 61000-4-2:2009
IEC 61000-4-3:2006+A1:2007+A2:2010/ EN 61000-4-3:2006+A1:2008+A2:2010
IEC 61000-4-4:2004+A1:2010/ EN 61000-4-4:2004+A1:2010
IEC 61000-4-5:2005/ EN 61000-4-5:2006
IEC 61000-4-6:2008/ EN 61000-4-6:2009
IEC 61000-4-11:2004/ EN 61000-4-11:2004
1. The product is intended for use in non-residential/non-domestic environments. Use of the
product in residential/domestic environments may cause electromagnetic interference.
2. Connection of the instrument to a test object may produce radiations beyond the specified
limit.
3. Use high-performance shielded interface cable to ensure conformity with the EMC standards
listed above.
Safety Standard
IEC 61010-1:2010/ EN 61010-1:2010

IT8500+ Programming Guide
Copyright © ITECH Electronic Co., Ltd. v
Contents
Certification and Quality Assurance............................................................................................................i
Warranty Service.........................................................................................................................................i
Limitation of Warranty.................................................................................................................................i
Safety Signs................................................................................................................................................i
Safety Precautions.....................................................................................................................................ii
Environmental Conditions..........................................................................................................................ii
Regulation Tag.......................................................................................................................................... iii
Waste Electrical and Electronic Equipment (WEEE) Directive.................................................................iii
Compliance Information............................................................................................................................iv
Chapter1 Remote Control .................................................................................................................1
1.1 Overview ..............................................................................................................................................1
1.2 SCPI Command Introduction ...............................................................................................................1
1.3 Command Type of SCPI......................................................................................................................1
1.4 Message Type of SCPI........................................................................................................................3
1.5 Response Data Type ...........................................................................................................................5
1.6 Command Format................................................................................................................................5
1.7 Data Type.............................................................................................................................................7
1.8 Remote Interface Communication .......................................................................................................8
1.8.1 Communication Modules Intruduction.........................................................................................8
1.8.2 Communication with PC ............................................................................................................10
Chapter2 SCPI Status Register.......................................................................................................13
Chapter3 Essential Commands......................................................................................................15
SYSTem:ERRor?.....................................................................................................................................15
SYSTem:VERSion?.................................................................................................................................15
SYSTem:SENSe[:STATe] <bool>............................................................................................................15
SYSTem:SENSe[:STATe]?......................................................................................................................16
SYSTem:LOCal........................................................................................................................................16
SYSTem:REMote.....................................................................................................................................16
SYSTem:RWLock....................................................................................................................................17
Chapter4 Status Commands...........................................................................................................18
STATus:QUEStionable[:EVENt]? ............................................................................................................18
STATus:QUEStionable:CONDition?........................................................................................................18
STATus:QUEStionable:ENABle <NRf+>.................................................................................................18
STATus:QUEStionable:ENABle?.............................................................................................................19
STATus:OPERation[:EVENt]? .................................................................................................................19
STATus:OPERation:CONDition?.............................................................................................................20
STATus:OPERation:ENABle <NRf+>......................................................................................................20
STATus:OPERation:ENABle? .................................................................................................................21
Chapter5 Input Settings ..................................................................................................................22
[SOURce:]INPut <bool>...........................................................................................................................22
[SOURce:]INPut?.....................................................................................................................................22
[SOURce:]INPut:SHORt <bool> ..............................................................................................................22
[SOURce:]INPut:SHORt? ........................................................................................................................23
[SOURce:]CURRent:RANGe <NRf+> .....................................................................................................23
[SOURce:]CURRent:RANGe?.................................................................................................................24
[SOURce:]VOLTage:RANGe <NRf+> .....................................................................................................24
[SOURce:]VOLTage:RANGe?.................................................................................................................25
[SOURce:]VOLTage:RANGe:AUTO[:STATe].......................................................................................25
[SOURce:]CURRent:SLEW[:BOTH] <NRf+>...........................................................................................26
[SOURce:]CURRent:SLEW[:BOTH]? ......................................................................................................26
[SOURce:]CURRent:SLEW:RISE <NRf+>..............................................................................................26
[SOURce:]CURRent:SLEW:RISE?..........................................................................................................27
[SOURce:]CURRent:SLEW:FALL <NRf+>..............................................................................................27
[SOURce:]CURRent:SLEW:FALL?..........................................................................................................28
[SOURce:]CURRent:PROTection[:LEVel] <NRf+> .................................................................................28
[SOURce:]CURRent:PROTection[:LEVel]?.............................................................................................29
[SOURce:]POWer:PROTection[:LEVel] <NRf+>.....................................................................................29

IT8500+ Programming Guide
Copyright © ITECH Electronic Co., Ltd. vi
[SOURce:]POWer:PROTection[:LEVel]?.................................................................................................30
[SOURce:]VOLTage:[LEVel:]ON <NRf+>................................................................................................30
[SOURce:]Voltage:[LEVel:]ON?...............................................................................................................30
[SOURce:]Voltage:[LEVel:]OFF <NRf+> .................................................................................................31
[SOURce:]Voltage:[LEVel:]OFF?.............................................................................................................31
[SOURce:]FUNCtion <function> ..............................................................................................................32
[SOURce:]MODE <function> ...................................................................................................................32
[SOURce:]FUNCtion?..............................................................................................................................32
[SOURce:]MODE?...................................................................................................................................32
[SOURce:]CURRent[:LEVel][:IMMediate][:AMPLitude] <NRf+>..............................................................33
[SOURce:]CURRent[:LEVel][:IMMediate][:AMPLitude]? .........................................................................33
[SOURce:]VOLTage[:LEVel][:IMMediate][:AMPLitude] <NRf+>..............................................................34
[SOURce:]VOLTage[:LEVel][:IMMediate][:AMPLitude]? .........................................................................34
[SOURce:]POWer[:LEVel][:IMMediate][:AMPLitude] <NRf+> .................................................................35
[SOURce:]POWer[:LEVel][:IMMediate][:AMPLitude]?.............................................................................35
[SOURce:]RESistance[:LEVel][:IMMediate][:AMPLitude] <NRf+>..........................................................36
[SOURce:]RESistance[:LEVel][:IMMediate][:AMPLitude]?......................................................................36
[SOURce:]DYNamic:HIGH[:LEVel] <NRf+> ............................................................................................36
[SOURce:]DYNamic:HIGH[:LEVel]?........................................................................................................37
[SOURce:]DYNamic:HIGH:DWELl <NRf+>.............................................................................................37
[SOURce:]DYNamic:HIGH:DWELl? ........................................................................................................38
[SOURce:]DYNamic:LOW[:LEVel] <NRf+>.............................................................................................38
[SOURce:]DYNamic:LOW[:LEVel]?.........................................................................................................39
[SOURce:]DYNamic:LOW:DWELl <NRf+>..............................................................................................39
[SOURce:]DYNamic:LOW:DWELl?.........................................................................................................40
[SOURce:]DYNamic:SLEW <NRf+>........................................................................................................40
[SOURce:]DYNamic:SLEW? ...................................................................................................................41
[SOURce:]DYNamic:SLEW:RISE <NRf+> ..............................................................................................41
[SOURce:]DYNamic:SLEW:RISE?..........................................................................................................41
[SOURce:]DYNamic:SLEW:FALL <NRf+>..............................................................................................42
[SOURce:]DYNamic:SLEW:FALL?..........................................................................................................42
[SOURce:]DYNamic:MODE <mode>.......................................................................................................43
[SOURce:]DYNamic:MODE?...................................................................................................................43
Chapter6 Measure Commands .......................................................................................................44
MEASure[:SCALar]:VOLTage[:DC]? .......................................................................................................44
MEASure[:SCALar]:VOLTage:MAXimum?..............................................................................................44
MEASure[:SCALar]:VOLTage:MINimum?...............................................................................................44
MEASure[:SCALar]:VOLTage:PTPeak?..................................................................................................45
MEASure[:SCALar]:CURRent[:DC]? .......................................................................................................45
MEASure[:SCALar]:CURRent:MAXimum?..............................................................................................45
MEASure[:SCALar]:CURRent:MINimum?...............................................................................................46
MEASure[:SCALar]:CURRent:PTPeak?..................................................................................................46
MEASure[:SCALar]:POWer[:DC]?...........................................................................................................46
MEAS[:SCALar]:RESistance[:DC]? .........................................................................................................47
Chapter7 OCP Testing Commands................................................................................................48
OCP[:STATe] <bool>...............................................................................................................................48
OCP[:STATe]?.........................................................................................................................................48
OCP:ISTart <NRf+>.................................................................................................................................48
OCP:ISTart?.............................................................................................................................................49
OCP:IEND <NRf+> ..................................................................................................................................49
OCP:IEND?..............................................................................................................................................49
OCP:STEP...............................................................................................................................................50
OCP:STEP?.............................................................................................................................................50
OCP:DWELl <NRf+>................................................................................................................................50
OCP:DWEL?............................................................................................................................................51
OCP:VTRig <NRf+>.................................................................................................................................51
OCP:VTRig? ............................................................................................................................................52
OCP:RESult[:OCP]? ................................................................................................................................52
OCP:RESult:PMAX?................................................................................................................................52
Chapter8 Peak Testing Commands................................................................................................54

IT8500+ Programming Guide
Copyright © ITECH Electronic Co., Ltd. vii
PEAK[:STATe] <bool> .............................................................................................................................54
PEAK CLEar ............................................................................................................................................54
PEAK:VOLTage:MAXimum? ...................................................................................................................54
PEAK:VOLTage:MINimum?.....................................................................................................................54
PEAK:CURRent:MAXimum? ...................................................................................................................55
PEAK: CURRent:MINimum?....................................................................................................................55
Chapter9 Voltage Rise/Fall Time Test............................................................................................ 56
TIME:VOLTage:LOW <Voltage>............................................................................................................56
TIME:VOLTage:LOW?............................................................................................................................56
TIME:VOLTage:HIGH <Voltage>...........................................................................................................56
TIME:VOLTage:HIGH?...........................................................................................................................57
TIME:VOLTage:UP?...............................................................................................................................57
TIME:VOLTage:DOWN?.........................................................................................................................57
Chapter10 Timing Test Commands..................................................................................................58
TIMing[:STATe].......................................................................................................................................58
TIMing:LOAD:SETTing ..........................................................................................................................58
TIMing:LOAD:MODE..............................................................................................................................59
TIMing:LOAD:VALue..............................................................................................................................59
TIMing:TSTart:SOURce .........................................................................................................................60
TIMing:TSTart:EDGE..............................................................................................................................60
TIMing:TSTart:LEVel..............................................................................................................................60
TIMing:TEND:SOURce...........................................................................................................................61
TIMing:TEND:EDGE ...............................................................................................................................61
TIMing:TEND:LEVel ...............................................................................................................................62
TIMing:RESult.........................................................................................................................................62
Chapter11 CR-LED Commands ........................................................................................................63
LED:VOLTage.........................................................................................................................................63
LED:CURRent.........................................................................................................................................63
LED:RCOeff ............................................................................................................................................64
Chapter12 IEEE488 Commands........................................................................................................65
*CLS - Clear Status..................................................................................................................................65
*ESE <NRf> - Event Enable ....................................................................................................................65
*ESE?.......................................................................................................................................................66
*ESR? ......................................................................................................................................................66
*IDN?........................................................................................................................................................66
*OPC........................................................................................................................................................67
*OPC?......................................................................................................................................................68
*PSC ........................................................................................................................................................68
*PSC? ......................................................................................................................................................68
*RCL.........................................................................................................................................................69
*RST.........................................................................................................................................................69
*SAV.........................................................................................................................................................69
*SRE ........................................................................................................................................................70
*SRE? ......................................................................................................................................................70
*STB?.......................................................................................................................................................71
*TST?.......................................................................................................................................................71
*TRG ........................................................................................................................................................71
Chapter13 Error Messages ...............................................................................................................73

Remote Control
Copyright © ITECH Electronic Co., Ltd. 1
Chapter1 Remote Control
1.1 Overview
This chapter will provide following remote configuration introductions:
⚫SCPI Command Introduction
⚫Command type
⚫Command format
⚫Data format
⚫Remote Operation
1.2 SCPI Command Introduction
SCPI is short for Standard Commands for Programmable Instruments which
defines a communication method of bus controller and instrument. It is based
on ASCII and supply for testing and measuring instruments. SCPI command is
based on hierarchical architecture which also known as tree system. In this
system, Relevant Command is returned to a common node or root, so that a
subsystem is formed.
A part of OUTPut subsystem is listed below:
OUTPut:
SYNC {OFF|0|ON|1}
SYNC:
MODE {NORMal|CARRier}
POLarity {NORMal|INVerted}
OUTPut is the root class keyword, SYNC is the second keyword, MODE and
POLarity are the third keyword. Colon(:) is used for separating the command
keyword and the next level keyword.
1.3 Command Type of SCPI
SCPI has two types of commands, common and subsystem.
⚫Common commands generally are not related to specific operation but to
controlling overall electronic load functions, such as reset, status, and
synchronization. All commoncommands consist of a three-letter mnemonic
preceded by an asterisk: *RST *IDN? *SRE 8.
⚫Subsystem commands perform specific electronic load functions. They are
organized into an inverted tree structure with the "root" at the top. The
following figure shows a portion of a subsyste command tree, from which
you access the commands located along the various paths.

Remote Control
Copyright © ITECH Electronic Co., Ltd. 2
Multiple commands in a message
Multiple SCPI commands can be combined and sent as a single
message with one message terminator. There are two important
considerations when sending several commands within a single
message:
⚫Use a semicolon to separate commands within a message.
⚫Head paths influence how the instrument interprets commands.
We consider the head path as a string which will be inserted in front of
every command of a message. As for the first command of a message,
the head path is a null string; for each subsequent command, the head
path is a string which is defined to form the current command until and
including the head of the last colon separator. A message with two
combined commands: CURR:LEV 3;PROT:STAT OFF
The example indicates the effect of semicolon and explains the concept
of head path. Since the head path is defined to be "CURR" after "curr: lev
3", the head of the second command, "curr", is deleted and the
instrument explains the second command as: CURR:PROT:STAT OFF
If "curr" is explicitly included in the second command, it is semantically
wrong. Since combining it with the head path will become
"CURR:CURR:PROT:STAT OFF", resulting in wrong command.
Movement in the subsystem
In order to combine commands from different subsystems, you need to
be able to reset the header path to a null string within a message. You do
this by beginning the command with a colon (:), which discards any
previous header path. For example, you could clear the output protection
and check the status of the Operation Condition register in one message
by using a root specifier as follows:
PROTection:CLEAr;:STATus:OPERation:CONDition?
The following message shows how to combine commands from different
subsystems as well as within the same subsystem:
POWer:LEVel 200;PROTection 28; :CURRent:LEVel 3;PROTection:STATe ON
Note the use of the optional header LEVel to maintain the correct path
within the voltage and current subsystems, and the use of the root
specifier to move between subsystems.
Including Common Commands
You can combine common commands with subsystem commands in the
same message. Treat the common command as a message unit by
separating it with a semicolon (the message unit separator). Common
commands do not affect the header path; you may insert them anywhere
in the message.
VOLTage:TRIGgered 17.5;:INITialize;*TRG
OUTPut OFF;*RCL 2;OUTPut ONIT872X-3X SCPI Communication protocol 17
Case sensitivity
Common commands and SCPI commands are not case sensitive. You
can use upper or lower, for example:

Remote Control
Copyright © ITECH Electronic Co., Ltd. 3
*RST = *rst
:DATA? = :data?
:SYSTem:PRESet = :system:preset
Long-form and short-form versions
A SCPI command word can be sent in its long-form or short-form version.
However, the short-form version is indicated by upper case characters.
Examples:
:SYSTem:PRESet long-form
:SYST:PRES short form
:SYSTem:PRES long-form and short-form combination
Note that each command word must be in long-form or short-form, and
not something in between.
For example, :SYSTe:PRESe is illegal and will generate an error. The
command will not be executed.
Query Observe the following precautions with queries:
⚫Set up the proper number of variables for the returned data. For example, if
you are reading back a measurement array, you must dimension the array
according to the number of measurements that you have placed in the
measurement buffer.
⚫Read back all the results of a query before sending another command to
the electronic load. Otherwise a Query Interrupted error will occur and the
unreturned data will be lost.
1.4 Message Type of SCPI
There are two types of SCPI messages, program and response.
⚫program message: Aprogram message consists of one or more properly
formatted SCPI commands sent from the controller to the electronic load.
The message, which may be sent at any time, requests the electronic load
to perform some action.
⚫response message:A response message consists of data in a specific
SCPI format sent from the electronic load to the controller. The electronic
load sends the message only when commanded by a program message
called a "query."
The next figure illustrates SCPI message structure:

Remote Control
Copyright © ITECH Electronic Co., Ltd. 4
The Message Unit
The simplest SCPI command is a single message unit consisting of a command
header (or keyword) followed by a message terminator. The message unit may
include a parameter after the header. The parameter can be numeric or a
string.
VOLTage 20<NL>
Headers Headers, also referred to as keywords, are instructions recognized by the
electronic load. Headers may be either in the long form or the short form. In the
long form, the header is completely spelled out, such as VOLTAGE, STATUS,
and DELAY. In the short form, the header has only the first three or four letters,
such as VOLT, STAT, and DEL.
Query Indicator
Following a header with a question mark turns it into a query (VOLTage?,
VOLTage:PROTection?). If a query contains a parameter, place the query
indicator at the end of the last header(VOLTage:PROTection?MAX).
Message Unit Separator
When two or more message units are combined into a compound message,
separate the units with a semicolon (STATus:OPERation?;QUEStionable?).
Root Specifier When it precedes the first header of a message unit, the colon becomes the
root specifier. It tells the command parser that this is the root or the top node of
the command tree.
Message Terminator
A terminator informs SCPI that it has reached the end of a message. Three
permitted message terminators are:
⚫newline (<NL>),decimal 10 or hexadecimal 0X0A in ASCII.
⚫end or identify (<END>)
⚫both of the above (<NL><END>).
In the examples of this guide, there is an assumed message terminator at the
end of each message.
Command execution rules
⚫Commands execute in the order that they are presented in the program
message.
⚫An invalid command generates an error and, of course, is not executed.
⚫Valid commands that precede an invalid command in a multiple command
program message are executed.
⚫Valid commands that follow an invalid command in a multiple command
program message are ignored.

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1.5 Response Data Type
Character strings returned by query statements may take either of the following
forms, depending on the length of the returned string:
<CRD>
Character Response Data. Permits the return of character strings.
<AARD>
Arbitrary ASCII Response Data. Permits the return of undelimited
7-bit ASCII. This data type has an implied message terminator.
<SRD>
String Response Data. Returns string parameters enclosed in
double quotes
Response messages
A response message is the message sent by the instrument to the computer in
response to aquery command.
Sending a response message
Afte sending a query command, the response message is placed in the Output
Queue. When the IT8500+ Series is then addressed to talk, the response
message is sent from the Output Queue to the computer.
Multiple response messages
If you send more than one query command in the same program message (see
the paragraph entitled, “Multiple Command Messages”), the multiple response
messages for all the queries is sent to the computer when the IT8500+ Series is
addressed to talk. The responses are sent in the order that the query
commands were sent and are separated by semicolons (;). Items within the
same query are separated by commas (,). The following example shows the
response message for a program message that contains four single item query
commands:
0; 1; 1; 0
Response message terminator (RMT)
Each response is terminated with an LF (line feed) and EOI (end or identify).
The following example shows how a multiple response message is terminated:
0; 1; 1; 0; <RMT>
Message exchange protocol
Two rules summarize the message exchange protocol:
Rule 1.You must always tell the IT8500+ Series what to send to the computer.
The following two steps must always be performed to send information from the
instrument other computer:
1. Send the appropriate query command(s) in a program message.1.
2. Address the IT8500+ Series to talk.
Rule 2.The complete response message must be received by the computer
before another program message can be sent to the IT8500+ Series.
1.6 Command Format
Formats for command display are as follows:
[SOURce[1|2]:]VOLTage:UNIT {VPP|VRMS|DBM}

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[SOURce[1|2]:]FREQuency:CENTer
{<frequency>|MINimum|MAXimum|DEFault}
Based on the command syntax, most commands (and certain Parameter) are
expressed in both upper and lower cases. Upper case refers to abbreviation of
commands. Shorter program line may send commands in abbreviated format.
Long-format commands may be sent to ensure better program readability.
For example, both formats of VOLT and VOLTAGE are acceptable in the above
syntax statements. Upper or lower case may be used. Therefore, formats of
VOLTAGE, volt and Volt are all acceptable. Other formats (such as VOL and
VOLTAG) are invalid and will cause errors.
⚫Parameter options with given command strings are included in the brace
({ }). The brace is not sent along with command strings.
⚫Vertical stripes (|) separate several parameter options with given command
strings. For example, {VPP|VRMS|DBM} indicates that you may assign
"APP", "VRMS" or "DBM" in the above commands. Vertical stripes are not
sent along with command strings.
⚫Angle brackets (< >) in the second example indicates that a value must be
assigned to the parameter in the brace. For example, the parameter in the
angle bracket is <frequency> in the above syntax statements. Angle
brackets are not sent along with command strings. You must assign a value
(such as "FREQ:CENT 1000") to the parameter, unless you select other
options displayed in the syntax (such as "FREQ:CENT MIN").
⚫Some syntax elements (such as nodes and Parameter) are included in
square brackets ([ ]). It indicates that these elements can be selected and
omitted. Angle brackets are not sent along with command strings. If no
value is assigned to the optional Parameter, the instrument will select a
default value. In the above examples, "SOURce[1|2]" indicates that you
may refer to source channel 1 by "SOURce" or "SOURce1" or "SOUR1" or
"SOUR". In addition, since the whole SOURce node is optional (in the
square bracket), you can refer to the channel 1 by omitting the whole
SOURce node. It is because the channel 1 is the default channel for
SOURce language node. On the other hand, if you want to refer to channel
2, "SOURce2" or "SOUR2" must be used in the program line.
Colon (:) It is used to separate key words of a command with the key words in next level.
As shown below:
APPL:SIN 455E3,1.15,0.0
In this example, APPLy command assigns a sine wave with frequency of 455
KHz, amplitude of 1.15 V and DC offset of 0.0 V.
Semicolon (;) It is used to separate several commands in the same subsystem and can also
minimize typing. For example, to send the following command string:
TRIG:SOUR EXT; COUNT 10
has the same effect as sending the following two commands:
TRIG:SOUR EXT
TRIG:COUNT 10
Question mark (?)
You can insert question marks into a command to query current values of most
Parameter. For example, the following commands will trigger to set the count as

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10:
TRIG:COUN 10
Then, you may query count value by sending the following command:
TRIG:COUN?
You may also query the allowable minimum or maximum count as follows:
TRIG:COUN?MIN
TRIG:COUN?MAX
Comma (,) If a command requires several Parameter, then a comma must be used to
separate adjacent Parameter.
Space You must use blank characters, [TAB] or [Space] to separate Parameter with
key words of commands.
Generic commands (*)
Execute functions like reset, self inspection and status operation. Generic
commands always start with a asterisk (*) and occupy 3 character sizes,
including one or more Parameter. Key words of a command and the first
parameter are separated by a space. Semicolon (;) can separate several
commands as follows:
*RST; *CLS; *ESE 32; *OPC?
Command terminator
Command strings sent to the instrument must end with a <Newline> (<NL>)
character. IEEE-488 EOI (End or Identify) information can be used as <NL>
character to replace termination command string of <NL> character. It is
acceptable to place one <NL> after a <Enter>. Termination of command string
always resets current SCPI command path to root level.
Note
As for every SCPI message with one query sent to the instrument, the instrument will
use a <NL> or newline sign (EOI) to terminate response of return. For example, if
"DISP:TEXT?" is sent, <NL> will be placed after the returned data string to terminate
response. If an SCPI message includes several queries separated by semicolon
(such as "DISP?;DISP:TEXT?"), <NL> will terminate response returned after
response to the last query. In all cases, the program must read <NL> in response
before another command is sent to the instrument, otherwise errors will be caused.
1.7 Data Type
SCPI language defines several data types used for program message and
response messages.
⚫Numerical parameter
Commands requiring numerical Parameter support the notations of all common
decimal notations, including optional signs, decimal points, scientific notation,
etc. Special values of numerical Parameter are also acceptable, such as MIN,
MAX and DEF. In addition, suffixes for engineering units can also be sent
together with numerical Parameter (including M, k, m or u). If the command
accepts only some specific values, the instrument will automatically round the
input Parameter to acceptable values. The following commands require
numerical Parameter of frequency value:
[SOURce[1|2]:]FREQuency:CENTer {<Frequency>|MINimum|MAXimum}

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⚫Discrete parameter
Discrete Parameter are used for settings with limited number of programming
values (such as IMMediate, EXTernal or BUS). They can use short and long
format like key words of commands. They may be expressed in both upper and
lower case. The query response always returns uppercase Parameter in short
format. The following commands require discrete Parameter in voltage unit:
[SOURce[1|2]:]VOLTage:UNIT {VPP|VRMS|DBM}
⚫Boolean parameter
Boolean Parameter refer to true or false binary conditions. In case of false
conditions, the instrument will accept "OFF" or "0". In case of true conditions,
the instrument will accept "ON" or "1". In query of Boolean settings, the
instrument will always return "0" or "1". Boolean Parameter are required by the
following commands:
DISPlay {OFF|0|ON|1}
⚫ASCII string Parameter
String Parameter may actually include allASCII character sets. Character
strings must start and end with paired quotation marks; and single quotation
marks or double quotation marks are both allowed. Quotation mark separators
may also act as one part of a string, they can be typed twice without any
character added between them. String parameter is used in the following
command:
DISPlay:TEXT <quoted string>
For example, the following commands display message of "WAITING..."
(without quotation marks) on the front panel of the instrument.
DISP:TEXT "WAITING..."
Single quotation marks may also be used to display the same message.
DISP:TEXT 'WAITING...'
1.8 Remote Interface Communication
1.8.1 Communication Modules Intruduction
The DB9 interface connector on the rear panel of the load
(IT8511+/IT8511A+/IT8512+/IT8512A+/IT8512B+/IT8512C+/IT8512H+/IT8513
A+/IT8513C+) is TTL voltage level, which needs to be connected to the serial
port of the PC through level conversion. The optional communication module is
IT-E121/IT-E121A/IT-E122/IT-E123.
The IT8513B+/IT8514B+/IT8514C+/IT8516C+ load includes standard RS232
and USB communication interface.
Do not connect the electronic load (IT8511+/IT8511A+/IT8512+/IT8512A+/
IT8512B+/IT8512C+/IT8512H+/IT8513A+/IT8513C+) with a standard RS232
cable, which may result in damage to the instrument.
IT-E121 Communication Module
The DB9 interface connector on the rear panel of the DC load is TTL voltage
level; you can use the communication module IT-E121 and a standard RS232
extension cable to connect the DB9 interface connector of the DC load and the
RS-232 interface connector of computer for the communication.

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IT-E121A Communication Module
The DB9 interface connector on the rear panel of the DC load is TTL voltage
level; you can use the communication module IT-E121A and a standard RS232
extension cable to connect the DB9 interface connector of the DC load and the
RS-232 interface connector of computer for the communication.
IT-E121A is derived on the basis of IT-E121, the main difference between them
is that the DB9 interface connector of the RS232 changes from female to male,
so that can be directly connected to the standard LAN interface.
IT-E121A communication cable
IT-E122 Communication Module
The DB9 interface connector on the rear panel of the DC load is TTL voltage
level; IT-E122 has a USB interface (male connector B) on one end, you can use
IT-E122 and a standard USB extension cable (type B female connector at one
end and typeA at one end) to connect the DB9 interface connector of the DC
load and the USB interface connector of computer for the communication.
After connecting the load and computer by USB, you need to install IT-E122
driver (download from
http://www.itech.sh/support/Down-3.htm?model=IT-E122%20%E5%85%89%E
9%9A%94%E7%A6%BB%E9%80%9A%E8%AE%AF%E6%8E%A5%E5%8F
%A3%E9%A9%B1%E5%8A%A8 or contact ITECH agent). The device
manager of PC will display ‘Prolific USB-to-Serial COM Port’ after installing.

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IT-E123 Communication Module
The DB9 interface connector on the rear panel of the DC load is TTL voltage
level; The interface on both side port of IT-E123 are DB9 interface and RS485
interface, you can use the communication module IT-E123 and an a standard
RS485-RS232 conversion cable to connect the DB9 interface connector of the
DC load and the RS-232 interface connector of computer for the
communication.
RS485 pins
1.8.2 Communication with PC
Before using the remote operation mode, please make sure that the baud rate
and communication address in the DC load are the same as in the computer
software, otherwise, the communication will fail, you can change the baud rate
and communication address from the front panel or from computer.
DB9 Serial Port
In order for the computer to communicate with the DC load, both must be set to
the same RS-232 settings. These communication settings are:
1. Baud rate: 4800,9600,19200 and 38400 are selectable, default setting is

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9600.
2. Data bit: 8 bit
3. Stop bit: 1
4. Parity: None
5. Address: the range is from 0 to 31, default setting is 0
Start Bit
8 Data Bits
Parity=None
Stop Bit
RS-232 IT8513B+/IT8514B+/IT8514C+/IT8516C+ electronic load has a DB9 interface
on rear panel. Connect E-load and computer by cable of COM ends (DB9).
Composite key [Shift] + [8] on front board can be used to enter system menu
for activation.
⚫RS-232 Interface
In RS-232 interface, all SCPI commands can be used for programming. If
RS-232 interface is selected, in accordance with internal connection of data
terminal equipment (DTE) and data communication equipment (DCE) as
defined in EIARS-232, the load is connected to another DTE (e.g., PC COM
interface) with direct-connected Modem cable.
RS232 Pins of Plug
Base Pin
Number
Description
1
No conjunction
2
TXD, data transmission
3
RXD, data receiving
4
No conjunction
5
GND, grounding
6
No conjunction
7
CTS, clear to send
8
RTS, request to send
9
No conjunction
⚫Communication Setup
Please ensure the PC and the load have the same configuration in the following
items.
Baudrate: 9600(4800, 9600, 19200, 38400). You could enter the system menu
to set the baudrate.
Data bit: 8
Stop bit: 1
Parity bit: (none, even, odd)